April, '13] BRIXTON: WALNUT WEEVIL 197 



from organisms under different temperature conditions; but under 

 similar moisture, food and gas conditions conducted at different 

 times of the year to the measured difference in temperature is hardly 

 justifiable. I regard the control of the sunlight variable as the most 

 difficult of all the climatic variables in this sort of study. 



Mr. E. p. Felt: I want to call attention to an apparatus which 

 might be useful to entomologists along this line, and that is a very 

 efficient device for maintaining low temperature. It is simply a 

 series of furnace pipes passing through the ordinary type of cold 

 chamber and packed with ice and salt. One or more pipes may be 

 used and by varying the relative amount of salt and ice considerable 

 modification in the temperature may be obtained. 



Mr. E. C. Cotton: Regarding the question of sunlight I think that 

 for most experiments it is not an important factor. If it is, one can 

 darken the room and use artificial light. With an arc light using 

 carbons impregnated with certain chemicals we can closely simulate 

 daylight. In regard to Dr. Felt's suggestion I think that we are 

 making a mistake by attempting to cool the air by means of pipes 

 within the room itself. It is impossible to hold the temperature 

 constant with cooling pipes of any kind in the room because of resid- 

 ual cooling from the cold mass of metal after the absorbing agent 

 (brine or expanding gas) has been shut off. I believe that it is neces- 

 sary to cool or heat the air outside of the room using a thermo-regu- 

 lator to determine when and what kind shall be introduced. I find 

 in our work that an electric regulator is out of the question, the regu- 

 lator we are using depends upon the expansion of gases. 



President Hunter: The next paper will be presented by Dr. 

 Britton. 



RECENT STUDIES ON THE WEEVIL AND THE BUD MOTH 



OF THE WALNUT AND A SAWFLY ATTACKING 



BLACKBERRY 



By W. E. Britton, State Entomologist, New Haven, Conn. 



Attempts to grow the English or Persian Walnut, Juglans regia, as 

 well as certain other species of Juglans in Connecticut have almost 

 failed, largely because of two insects which attack the trees, the walnut 

 weevil or curculio, Conotrachehis juglandis Lee, and a ])ud moth be- 

 longing to the genus Acrohasis and probably referable to the species 

 canjm Grote. 



Studies of the life histories and habits and of the injuries caused by 

 these two pests, w^ere made during the past summer on the farm of 

 Dr. Robert T. Morris at Stamford and the walnut weevil was also 



